The Internet has developed very much both in respect of its contents and of the technology employed, since it began a few years ago. In the early days of the Internet, web sites included text only, and after a while graphics was introduced. As the Internet developed, many compressed standards, such as pictures, voice and video files, were developed and with them programs used to play them (called “players”). Initially, such files were downloaded to the user's workstation only upon his request, and extracted only by the appropriate player, and after a specific order from the user.
When, in the natural course of the development of the World Wide Web the search for a way to show nicer, interactive and animated Web Pages began, Sun Microsystems Inc. developed Java—a language that allows the webmaster to write a program, a list of commands—Network Executables—that will be downloaded to the user workstation without his knowledge, and executed by his browser at his workstation. The executables are used, e.g., to provide photographic animation and other graphics on the screen of the web surfer. Such executables have some ways approaching the user workstation's resources, which lead to a great security problem. Although some levels of security were defined in the Java language, it was very soon that a huge security hole was found in the language.
Since Java was developed, Microsoft developed ActiveX, which is another Network Executable format, also downloaded into the workstation. ActiveX has also security problems of the same kind.
The Internet has been flooded with “Network Executables” that may be downloaded—deliberately or without the knowledge of the users—into workstations within organizations. These codes generally contain harmless functions. Although usually safe, they may not meet the required security policy of the organization.
Once executed, codes may jam the network, cause considerable irreversible damage to the local database, workstations and servers, or result in unauthorized retrieval of information from the servers/workstations. Such elements may appear on Java applets, ActiveX components, DLLs and other object codes, and their use is increasing at an unparalleled pace. The majority of these small programs are downloaded into the organization unsolicited and uncontrolled. The enterprise has no way of knowing about their existence or execution and there is no system in place for early detection and prevention of the codes from being executed.
The security problem was solved partially by the browser manufacturers which allow the user to disable the use of executables. Of course this is not a reasonable solution, since all the electronic commerce and advertising are based on the use of executables. The security problem is much more serious once such an executable can approach the enterprise servers, databases and other workstations.
In a copending patent application of the same applicant herein, IL 120420, filed on Mar. 10, 1997 (and on Feb. 23, 1998 as PCT/IL98/00083), the specification of which is incorporated herein by reference, a method is described and claimed, for selectively preventing the downloading and execution of undesired Executable Objects in a computer, which comprises the steps of:                (a) providing one or more Control Centers, each connected to one or more gateways, each gateway serving one or more end user computers;        (b) providing means coupled to each of said gateways, to detect Executable Objects reaching said gateway, to analyze the header of each of said Executable Objects, and to determine the resources of the computer that the Executable Object needs to utilize;        (c) providing means coupled to each of said gateways, to store each end user computer Security Policy representing the resources, or combination of resources, that the administrator allows or does not allow an Executable Object to utilize within its destination, wherein the Security Policy is received from and/or stored in each of said one or more Control Centers;        (d) when an Executable Object is detected at the gateway:                    1. analyzing the header of said Executable Object;            2. determining the resources of the computer that the Executable Object needs to utilize;            3. comparing the resources of the computer that the Executable Object needs to utilize with the Security Policy and;                            (i) if the resources of the computer that the Executable Object needs to utilize are included in the list of the resources allowed for use by the Security Policy, allowing the Executable Object to pass through the gateway and to reach the computer which has initiated its downloading; and                (ii) if the resources of the computer that the Executable Object needs to utilize are included in the list of the resources prohibited for use by the Security Policy, preventing the Executable Object from passing through the gateway, thereby preventing it from reaching the computer which has initiated its downloading.                                                
A Control Center (CC) may be a central control unit, e.g., a PC or other computer, which is connected to a plurality of gateways, and which updates the memory means containing relevant date, e.g., the Security Policy. Once the CC is updated, e.g., by the addition of an additional limitation to the Security Policy, all gateways are updated at once. The use of the CC to control the operation of the security elements of the gateways obviates the need (which exists in prior art systems) to update each gateway every time that a change in policy is made.
A LAN Local Area Network) may be (but is not limited to), e.g., a network of computers located in an office or building. The LAN is typically connected to outside communications networks, such as the World Wide Web, or to more limited LANs, e.g., of a client or supplier, through one or more gateways. The larger the organization, the larger the number of gateways employed, in order to keep communications at a reasonable speed.
Generally speaking, a LAN can also be made of a plurality of smaller LANs, located geographically nearby or far apart, but even if small LANs are found within the same organization, the security requirements may vary from one department to the other, and it may be necessary to keep high security levels, including preventing Executables from migrating from one department to the other, even within the same organization.
The means coupled to each of said gateways, to detect Executable Objects reaching said gateway, to analyze the header of each of said Executable Objects, and to determine the resources of the computer that the Executable Object needs to utilize may be of many different types. Typically, the executable object is “trapped” and analyzed at the gateway by listening on the communication line to the TCP/IP protocol as well as to the object transfer protocols, such as SMTP, HTTP, FTP, etc. Hooking into the communication line and extracting the contents of the header of the executable object are steps which are understood by the skilled person, and which can be effected by means of conventional programming, and they are therefore not described herein in detail, for the sake of brevity.
Once the header of the Executable Object (EO) has been analyzed, comparing the resources of the computer that the EO needs to utilize with the Security Policy can be easily done, e.g., by comparing them with a look-up table provided to the gateway by the CC, which represents the Security Policy. Comparison can also be carried out against the data stored in the CC, and in such a case specific memory means and comparing means may not be necessary in the gateway. However, speed and performance considerations will often dictate that such operations be carried out at the gateway itself.
Prior art solutions provide for the analysis of communication taking place via a single port, Port 80, which is the port commonly employed for web surfing. However, today it is possible to surf the net through ports other than Port 80, while the HTTP server of the user, according to currently available technology, cannot work on a plurality of ports. Therefore, if more than one user employ a gateway simultaneously, prior art systems are ineffective since they are not suitable for the simultaneous analysis of communication taking place via other ports.
Another severe drawback is that a very strong HTTP server is needed to serve a plurality of users, when operating according to the prior art method.
In order to permit to analyze the executables “on the fly”, without hindering the downloading and he operation of harmless executables, another copending patent application of the same applicants herein (121815, filed Sep. 22, 1997, and corresponding PCT application PCT/IL98/00082, filed on Feb. 23, 1998) provides a method for processing Executable Objects, comprising:                (a) providing analysis means capable of non-interfering analysis of data packets transmitted on a communication line between a browser and an HTTP server on the web, said communication line being established through a gateway;        (b) analyzing the handshake between said browser and said server, to detect a “GET_” command sent by the user and an HTTP code sent in response by said server;        (c) when such an HTTP code is detected, analyzing the data packets transmitted by said server to said browser, by:                    (1) providing ordering means to order data packets received in non-sequential order, and to forward them in sequential order to header checking means;            (2) checking the data packets so as to analyze the contents of the header of the Executable Object, and to identify the resources of the system that it needs to employ;            (3) transmitting to said gateway data representing the resources of the system that the Executable Object needs to utilize; and            (4) providing data packet suppressing means coupled to said gateway, such that if the resources of the system that the Executable Object needs to utilize are not permitted according to the security policy set by the administrator, at least one data packet belonging to the 4Executable Object is suppressed, altered or damaged, so as to prevent the execution thereof by the browser.                        
The ever changing scene of Internet systems, however, requires that new solutions be provided to new threats which develop continuously, to add to the security provided by existing methods. Specifically, new Internet browsers are equipped with expanded capabilities, in addition to those needed for browsing the Internet, such as the ability to access local files and directories. Furthermore, other applications, such as, for instance, MS-Word or Visual-C++, allow browsing to be carried out directly without the need for an additional browser. In this situation, the separation that existed conventionally between Internet applications and other programs, does no longer exist. As a result, undesirable Executable Objects may be allowed access through “secure” applications, viz., through applications, such as a word processor, that were previously considered safe inasmuch as they did not allow for the access of EOs.
The art has so far failed to provide a solution to this problem, and it is clear that such a solution is urgently needed.